U.S. patent number 4,538,072 [Application Number 06/486,587] was granted by the patent office on 1985-08-27 for optical wand for reading ocr characters and bar code marks.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Josef Immler, Cornelis van der Sel.
United States Patent |
4,538,072 |
Immler , et al. |
August 27, 1985 |
Optical wand for reading OCR characters and bar code marks
Abstract
Optical wand for automatic character recognition including a
scanner unit designed to be a manually movable along a line of
print of a data carrier in order to recognize optical characters
and incorporating a light source for illuminating a scanning window
and a sensing device. A second scanner unit includes a second
sensing device and is designed for recognizing bar code marks. A
gun shaped housing forms a common case for both scanner units.
Inventors: |
Immler; Josef (Puchheim,
DE), van der Sel; Cornelis (Grafing, DE) |
Assignee: |
Siemens Aktiengesellschaft
(Berlin and Munich, DE)
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Family
ID: |
6161411 |
Appl.
No.: |
06/486,587 |
Filed: |
April 19, 1983 |
Foreign Application Priority Data
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Apr 20, 1982 [DE] |
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3214621 |
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Current U.S.
Class: |
250/568; 235/440;
382/318; 235/462.49; 235/472.03; 235/462.35 |
Current CPC
Class: |
G06K
7/10881 (20130101); G06K 9/2009 (20130101); G06K
7/109 (20130101) |
Current International
Class: |
G06K
7/10 (20060101); G06K 9/20 (20060101); G06K
007/10 () |
Field of
Search: |
;235/440,472,462,436
;382/62 ;250/216,239,566,568 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0062777 |
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Oct 1982 |
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EP |
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0063243 |
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Oct 1982 |
|
EP |
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Primary Examiner: Nelms; David C.
Assistant Examiner: Brophy; J. Jon
Attorney, Agent or Firm: Moran; John Francis
Claims
What is claimed is:
1. An optical wand for automatic character recognition designed to
be manually movable along a line of print of a data carrier for
recognizing optical characters and bar code marks, respectively and
including a scanner unit incorporating a light source for
illuminating a scanning window via reflected light and the portion
of the data carrier appearing therein, an optical system and a
sensing unit, said optical wand comprising:
a housing body having a nose section including a scanning tip with
the optical system being located within the nose section, the
housing body having a handle section adapted for manually gripping
and angularly extending away from the nose section and the nose
section includes a tip having an
aperture serving as the scanning window for the optical system
commonly utilized for scanning of both optical characters and bar
code marks and means for receiving the reflected light, and means
for deflecting said reflected light; and
said sensing unit being arranged in said housing and being composed
of first and second sensor devices, the first sensor device being
arranged in alignment with said aperture for directly receiving one
portion of reflected light and the second sensor device being
arranged for receiving another portion of the reflected light from
said deflecting means.
2. The optical wand as recited in claim 1, wherein said deflecting
means comprises a deflecting prism having an adjusting screw for
changing the distance of the deflecting prism from said second
sensor device.
3. The optical wand as recited in claim 2, wherein said optical
system further comprises:
a tubular support member having a first and a second end portion
and being replaceably mounted within said housing in alignment with
said scanning tip;
said first end of portion facing the scanning tip and bearing a
lens system, and the sensor devices being mounted onto said support
member in proximity of the second end portion;
an inner adjusting tube coaxially and slideably arranged within
said support member and bearing said deviating prism attached to
its inner wall adjacent to said second end portion of said support
member; and
means for moving and lacking said inner moving tube with respect to
said support member.
4. The optical wand as recited in claim 3, wherein said adjusting
and securing means further comprise:
a groove cut into the outer surface of the wall of the
adjusting tube in a direction perpendicular to the central axis of
the adjusting tube;
an opening provided in the wall of the supporting member in
alignment with said groove; and
a threaded opening provided in the wall of the supporting member
and a screw arranged therein for securing the slideably arranged
adjusting tube with respect to the support member in an adjusted
position.
5. The optical wand as recited in claim 4, wherein the first end
portion of the support member forms a guiding shoulder and the lens
system comprises a separate mount fastened to said guiding
shoulder; and wherein the second end portion comprises a collar for
mounting the sensor device for recognizing optical characters, an
opening in the side wall arranged opposite to said deviating prism,
and in alignment therewith a bearing surface provided on the outer
surface of said support member for attaching a sensor array for
recognizing bar code marks.
Description
BACKGROUND OF THE INVENTION
The invention is related to to an optical wand for automatic
character recognition including a scanner unit designed to be
manually movable along a line of print of a data carrier in order
to recognize optical characters. The hand held optical reader
includes a light source for illuminating a scanning window, and a
sensor device for sensing the area of the data carrier currently
appearing in the scanning window.
Such sensing devices are utilized with automatic character
recognition in order to convert visually readable characters
imprinted on a data carrier, i.e. a voucher, a letter or a label
directly into a format which can be automatically analyzed and
processed. The string of information corresponding to recognized
characters is usually furnished to a data processing system or a
peripheral unit such as a printer for further processing. By means
of an example, U.S. Pat. No. 4,250,488 discloses such an optical
device for automatic character recognition which is designed for
reading standardized alpha numeric optical characters, such device
is usually designated as optical character recognition (OCR)
reader.
A different group of automatic recognition devices incorporates
devices designed for recognizing coded data imprinted on labels.
The coded information is very often represented by so called bar
code marks and corresponding reading devices are commercially
available, one example is the Ruby Wand Light Pen, model 1240
manufactured and sold by Intermec, Lynnwood, Wa. 98036.
Automatic reading devices designed for recognizing bar code marks
have a structure which is quite different from above mentioned
devices suitable for optical character recognition. This is quite
understandable in view of the totally different appearance of the
printed information. OCR readers are designed to sense an area
appearing in the scanning window of the reader point-to-point and
in parallel thus enabling to reconstruct segments or at least
elements of a character. Bar code readers, on the contrary, are
much less complicated. A single sensing device associated with an
appropriate light source scans the series of bar codes and
interprets the apperance of black and white elements in dependence
upon a predetermined threshold and derives therefrom a pulse train
which is supplied to an evaluation unit.
Bar codes and OCR fonts are commercially utilized in various areas
of business and are preferably utilized for making different groups
of goods. OCR fonts are very often applied to checks, labels of
dresses and a variety of technical articles whereas the bar code
marking finds its main application for identifying packaged food.
It is conceivable that some businesses, such as department stores
sell goods belonging to either one of these two groups. It is
therefore necessary to provide for both types of reading devices.
This approach means some inconvenience for the organization of
sales in such departments stores; it is inefficient and especially
impractical for operators such as cashiers to work with different
wands for different groups of labels.
U.S. Patent. 3,410,991 discloses a reading device for a data
carrier bearing simultaneously a line of visually readable
characters and associated therewith corresponding bar code marks
imprinted below the respective optical characters. The known
reading device includes scanner units designed for sensing the
characters and the associated bar code marks simultaneously at
several horizontal levels in order to achieve a high scanning
immunity in view of tolerances of vertical misalignment of the
scanner. The known reading device, however, is not designed for
recognizing OCR fonts and bar code marks alternatively.
European Patent Application No. 0,062,777 discloses a combined OCR
and bar code reader utilizing a single area array for sensing OCR
fonts or bar codes. In other words, the sensor array designed for
sensing OCR fonts is also utilized for sensing bar code marks and
measures have to be taken in the evaluation unit to distinguish
between signal information associated with an OCR font and a bar
code, respectively. This kind of a combinative use of a single
sensing device for both groups of markings by means of a common
sensor array seems to make efficient use of a reading device for
different purposes but has some disadvantages. The general
difference between recognizing OCR fonts and bar code marks, has
been outlined above; it is therefore conceivable that a device
utilized for reading both types of markings cannot be as exactly
adjusted to all requirements as would be desirable for conditions
which are contradictory for reading optical characters and bar code
marks, respectively. Furthermore, in case of a failure of the
sensor device the entire reader will be out of order.
SUMMARY OF THE INVENTION
It is therefore a main object of the present invention to provide
for an improved hand held optical reader suitable for recognizing
alternatively both visually readable characters and bar code
marks.
It is a further object of the present invention to provide for such
a combined hand held wand which is specifically designed for high
performance with respect to both recognizing of visually readable
characters and bar code marks, the design taking into consideration
the significantly different conditions for recognizing both types
of markings.
It is a further object of the present invention to provide for such
a hand held wand which is designed to be manufactured, assembled
and maintained at low cost and still provides for a high
realibility.
These objects, as well as other objects which will become apparent
from the description which follows, are achieved by an improved
optical wand for automatic character recognition including a
scanner unit designed to be manually movable along a line of print
of a data carrier in order to recognize optical characters and
including a light source for illuminating a scanning window, and a
sensor device for sensing the portion of the data carrier appearing
in the scanning window. This optical wand incorporates a second
scanner unit including a second sensing device wherein the second
scanner unit is designed for recognizing bar code marks. In
addition, a gun shaped housing is provided which housing forms a
common case for both scanner units.
This structure combines the function of an OCR reading device and a
bar code reader in a manner that both sections can be alternatively
utilized for either OCR fonts or bar code marks, as the case may
be. In accordance with a preferred embodiment of the present
invention this housing includes a scanning tip and an optical
system arranged therein, wherein the optical system incorporates an
aperture commonly utilized for scanning both optical characters and
bar code marks and further includes means for deflecting a scanning
beam associated with one of the scanning units onto a respective
one of the sensor devices. This structure offers a possibility for
utilizing one optical system for sensing both types of markings,
wherein the different appearance of both types of markings and the
corresponding changing conditions for sensing the same are
advantageously utilized to deflect a portion of the reflected
light. Light beams are thus focused onto the sensing device
associated with sensing bar code marks without disturbance and loss
of light of the light portion illuminating the sensor array
associated with sensing visual characters.
Further details and advantages of the present invention will become
more apparent from the detailed description of preferred
embodiments, which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the invention may be had by reference to
the following description of preferred embodiments in conjunction
with the accompanying drawings, in which:
FIG. 1 shows schematically a sectional view of a hand held
wand;
FIG. 2 represents a block diagram of the sensing and evaluating
networks designed for use with the reading device of FIG. 1;
FIG. 3 represents a second embodiment by means of a sectional
partial view illustrating the design of a scanning tip for use with
such a combined hand held wand;
FIG. 4 illustrates schematically an optical system of another
embodiment of a combined hand held wand, wherein both sensor units
are integrated into one optical arrangement;
FIG. 5 represents a schematic illustration of the sensing window of
such a hard held wand and the corresponding image areas for
illuminating the sensor devices;
FIG. 6 represents a sectional view of a another embodiment of a
hand held wand incorporating an integrated, replaceable optical
system; and
FIG. 7 represents a sectional view taken along line 7--7 of FIG. 6
and illustrating details of the optical system.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The hand held wand shown in FIG. 1 is designed for use with
recognizing optical character recognition (OCR) fonts and coded
information imprinted on a data carrier in form of bar code marks,
as well. The reading device is provided with a gun shaped housing 1
and two sensor units 10, 11 arranged therein which allow for
recognizing an OCR font and bar code marks, respectively. Both
sensor units 10 and 11 are completely separated and arranged aside
from each other. Both sensor units have slightly different sensing
planes which are vertically spaced apart by a distance designated
by A. The illustration of FIG. 1 is approximately in size and it
may be thus obtained that this distance A in an actual
implementation has a size of several millimeters. This arrangement
makes it possible to select and activate one of the sensor units in
order to perform a corresponding recognition procedure simply by
tilting the manually operated hand held wand.
The sensing plane of the bar code sensor unit 11 is determined by
the tip of the sensor head 11/1 whereas the corresponding sensing
plane of the OCR sensor unit 10 is defined by a sensing window 10/1
in conjunction with a correspondingly arranged light source
arrangement 10/2. The hand held wand is in operative mode when an
indicator lamp 2 is illuminated. In this mode the hand held wand is
ready to be moved across a line of markings imprinted on a label, a
voucher etc., utilizing either sensor unit 10 or 11, as the case
may be in accordance with the type of markings to be scanned.
The recognition of sensed characters or coded markings, as such, as
of minor importance with respect to the present invention, is known
to those skilled in the art and is therefore not described in full
detail. However, an outline of the recognizing and evaluation
process will be given in the following in conjunction with the
block diagram of FIG. 2.
The OCR sensor unit 10 reproduces character segments on a sensor
array comprising a photodiode matrix 12, schematically indicated in
FIG. 1. Electronic signals corresponding to such character segments
are electronically preprocessed and digitalized in a recognizing
network 13. The sensor array 12 and this recognizing network are
commonly illustrated in FIG. 2 by one block designated 12/13. The
preprocessed signals are then supplied to an evaluating network 16
which may be implemented in the form of a microprocessor system.
Implementations of the recognizing network and the evaluating
network may be obtained from U.S. Pat. Nos. 4,250,488 and
4,246,570, respectively, further detailed description therefore is
deemed not be necessary. The processed signals are then furnished
to a modified bar code processing unit 21 for further processing
and transmission.
On the other hand, the optical signals representing the sensed bar
code information are supplied to an opto-electronic converter 14
for converting the same into electrical signals. These electrical
signals are amplified by means of an analog signal amplifier 15
connected to the output of converter 14. Output signals of the
analog amplifier 15 are forwarded to an analog-to-digital converter
20 and are then supplied in digital form to the same modified bar
code processing unit 21. This processing unit incorporates a bar
code evaluating unit 22 which derives bar code marks from the
received pulse train, eliminates noise signals and associates the
recognized marks with one of n predetermined bar codes.
Furthermore, the processing unit 21 recognizes the direction of the
course of the scanning process, i.e., it is recognized whether the
markings were sensed in forward direction or in backward direction.
Furthermore, the recognized code is evaluated and a character check
is executed for determining invalid codes.
Both sensor units are active simultaneously during the scanning
process, this means black/white transitions are recognized in both
sensor units and accordingly both the evaluating network 16 and the
bar code processing evaluating unit 22 are active in processing the
respective information supplied. To this reason, the different
results are discriminated by means of a further validity check
which is performed by a control unit 23 commonly coupled to both
evaluating networks. This control unit performs a transfer control
for information received from either one of the sensor units, on
the one hand and generates control instructions, on the other hand.
It includes, among others, a network for performing a validity
check of the electrical signals and the corresponding data based
upon the principle of highest probability. Depending upon the
result of this check the data blocks received from either the OCR
evaluating network 16 or from the bar code evaluating unit 22 are
selected and control signals are added identifying the selected
block as belonging to an OCR data block or bar code data block.
The output of the control unit is connected to inputs of an output
unit 24 which operates under control of an interface switch 25.
Output unit 24 and interface switch 25 and their specific functions
depend upon the characteristics of a terminal (not shown) or a
processing system which looks at the hand held wand as a
peripheral. The output unit 24 in cooperation with interface switch
25 has the object to operate as a transmitter for transmitting the
received data blocks with appropriate timing and framing aross an
interface schematically indicated by arrow 26 in accordance with
data transmission procedures specified by the interface
characteristic of a receiving unit (not shown). The processing unit
which may be implemented as a microprocessor system is ready for
evaluating further information representing scanned data as soon as
such data transmission is completed.
The embodiment represented in FIG. 1 is only one of several
possibilities for designing such a hand held wand for combinative
use incorporating two separate sensor units. FIG. 3 illustrates an
example of a different implementation of the same design concept
illustrated by means of a partial sectional view of a scanning tip
32 including a reflective-light sensor 30 incorporating the bar
code scanning unit wherein both scanning systems are separated from
each other by a dividing wall 35. The mounting area of the
reflective-light sensor 30 is designed as a receptacle wherein the
reflective-light sensor 30 is secured by means of a spring 31.
The scanning tip can be removed from the housing of the hand held
wand to make the reflective-light sensor 30 accessible and
removable by lifting the spring 31. This allows for easy assembly
and disassembly, thereby simplifying maintenance and test
procedures. A shielded multi-wire conductor 33 connects the
reflective-light sensor 30 whose operation corresponds to that of
the analog signal amplifier 15 shown in FIG. 2.
FIG. 4 represents another implementation of the optical system of
the combined hand held wand in an schematical illustration. This
implementation is in so far unique that both sensor units are
integrated with each other by providing a common scanning window
for the scanning operation of both sensor units. The scanning tip
52 incorporates just one light source arrangement 58 commonly used
for both operations. Reflected light--indicated by light beam
54--is received through a lens system 59 and is focused onto a
sensor array 12 which is provided for recognizing OCR character
segments. A part of the reflected light received through the lens
system 59 is deviated by means of an deviating prism 50 which
receiving surface is pitched by 45 degrees against the central
optical axis. The deviated light portion is focused on a bar code
detector 51 having a receiving surface arranged in parallel to the
central optical axis. The deviating prism is slideably arranged on
a wall forming the mount for the lens system 59 and bears an
adjusting screw 52 by means of which adjusting screw the distance
between the deviating prism 50 and the bar code detector 51 can be
corrected. This adjusting measure allows for forming an extremely
sharp image on the surface of the bar code detector 51. This
detector emits output signals which are further processed by means
of an amplifier 53 which corresponds to the analog signal amplifier
15 described in conjunction with FIG. 1.
The utilizing of the light source arrangement 58 and the lens
system 59 of the OCR scanning unit for scanning of bar code marks,
as well by means of deviating a portion of the reflected light is
made possible by a corresponding design of the lens system 59. The
reflected light beams 54 illuminate an area which corresponds to
the opening of scanning window and which is larger than the active
surface of the sensor array 12. The schematic of FIG. 5 represents
these conditions. The area designated by 43 corresponds to the
mentioned illuminated area whereas the surrounding rectangle 40
represents the outer dimensions of the sensor array 12 having an
active surface represented by a rectangle 42 located in the center
of the illuminated area 43. A rectangle 41, shown in broken lines,
corresponds to the front opening of the scanning tip 52 which
defines the scanning window. As may be obtained from this
schematic, all light beams falling outside of the rectangle 42 can
be utilized for deviating the same onto the reflective-light
detector 51 without interference with the OCR scanning unit.
A further preferred embodiment of the combined hand held wand
incorporating a replaceable optical system is illustrated in FIGS.
6 and 7, respectively wherein FIG. 7 shows a sectional view along
lines 7--7 of FIG. 6. This preferred embodiment includes an
integrated optical system 61 which is removably mounted in the
housing of the hand held wand by means of screws 60. The optical
system 61 includes a lens system and the sensor devices for bar
code marks and for OCR characters, as well. In alignment with the
optical central axis there is arranged a tubular support member 62
made of plastic which embraces an inner adjusting tube 64 being
slideably arranged within the same. This adjusting tube is made of
metal and bears the deviating prism 63 attaching to its inner
surface. This adjusting tube is accessable through an opening 66
provided in the support member. A groove 65 cut into the outer
surface of the wall of the adjusting tube 64 is locatred in
alignment with the opening 66 such that the adjusting tube 64 can
be slideably moved for adjustment by means of an screwdriver or any
other appropriate tool reaching through the opening 66. An end
portion of the support member 62 is form of a projecting ring 67
which forms a guiding element for the lens system. The lens system
in itself is provided with a separate mount 68 and the guiding ring
67 provides a snug fit for the mount 68 of the lens system.
The opposite end portion of the tubular support member 62
constitutes a flange including a precisely tolerated bearing
surface 69 for mounting the sensor array 12 provided for
recognizing OCR characters. In addition to this flange and opposite
to the mounted deviating prism 63 there is provided an opening 71
arranged in the side wall of the adjusting tube 64. In alignment
therewith a small circuit board 73 is mounted onto the outer
surface of the supporting member 62. This arrangement is designed
such that the light portion reflected from the deviating prism 63
is transmitted through the opening 71 and focused onto the bar code
sensor device which is mounted on the circuit board 73.
It is an essential feature of this design of a replaceable optical
system to enable an especially easy adjusting of the deviating
prism 63. This is achieved after mounting the sensor devices 12 and
70, respectively by means of a screwdriver or any appropriate tool
which is positioned through the opening 66 while penatrating into
the groove 65. In this manner the adjusting tube 64 can be moved
with respect to the supporting member 62 and can be secured in a
adjusted final position with respect to the supporting member 62 by
means of an adjusting screw 72.
The supporting member 62 constitutes the mount for the optical
system and the sensor devices, as well; this determines an
especially exactly tolerated arrangement which is unsensitive with
respect to temperature changes and vibrations caused by rough
handling of the hand held wand. It is a special feature of this
design that the entire optical system is assembled and adjusted
prior to fitting the same into the housing of the hand held. This
design concept allows for much less costly manufacturing.
The preferred embodiments described in conjunction with FIGS. 4, 6
and 7, respectively are designed to utilize the same scanning
window for scanning both OCR characters and bar code marks. This
structure had the advantage of being of the same handy shape and
design as it is known for available hand held wands utilized for
reading OCR characters only despite the fact that a second sensor
unit and associated networks are incorporated. The necessary
mechanical changes are limited to internal adjustments of the
support member for the lens system. High reliability, in addition,
for recognizing bar code marks is achieved since the bar code
detector can be implemented to show a bar shape. This is of special
advantage for various applications in practice. Printed bars to be
recognized often show flaws such as interruptions which can be
caused by printing the bars with matrixs printers or laser
printers. Such failures of print may lead to misinterpretations if
point shaped detectors are utilized for recognition whereas a bar
shaped active surface of the scanning unit does eliminate the
impact of such flaws. No additional electric power has to be
supplied as compared to conventional OCR readers, and
correspondingly no additional heat is developed within the scanning
tip. Even more, an additional reduction of the dissipated heat is
made possible by utilizing the light source arrangement 58 for
scanning OCR characters and for bar code marks, as well.
There has thus been shown and described a novel hand held wand for
recognizing both OCR characters and bar code marks, which fulfills
all the objects and advantages sought therefor. Many changes,
modifications, variations and other uses and applications of the
subject invention will, however, become apparent to those skilled
in the art after considering the specification and the accompanying
drawings, which disclose preferred embodiments thereof. All such
changes, modifications, variations and other uses and applications
which do not depart from the spirit and scope of the invention are
deemed to be covered by the invention which is limited only by the
claims which follows.
* * * * *